Stent delivery catheter positioning device

ABSTRACT

The present invention generally relates to a medical device and procedure for accurately positioning a catheter across a desired region within a patient&#39;s vasculature. In particular, the present invention provides a hub assembly unit that allows a physician to precisely position a stent within a vessel utilizing a stent delivery catheter. The hub assembly unit includes a fine adjustment mechanism. The fine adjustment mechanism extends or contracts the length of the hub assembly unit in controlled incremental units. These controlled fine displacements are then translated directly to the stent delivery or balloon dilation catheter.

CROSS-REFERENCE TO CO-PENDING APPLICATIONS

This application is a continuation of U.S. application Ser. No.09/784,762, filed Feb. 15, 2001.

FIELD OF THE INVENTION

The present invention generally relates to a medical device forpositioning a stent delivery or dilatation balloon catheter within thevascular system of a patient. More specifically, the present inventiondiscloses a hub assembly unit providing an operator the ability tofinely adjust the positioning of a stent delivery or a balloon dilationcatheter within a patient's vascular system.

BACKGROUND OF THE INVENTION

Percutaneous Transluminal Coronary Angioplasty (PTCA) is awell-established procedure for dilating stenosed vessel regions within apatient's vasculature. In this procedure, a balloon angioplasty catheteris introduced into the vasculature, typically through an incision in thefemoral artery in the groin. The balloon catheter is then advancedthrough the femoral artery, through the aortic arch, and into the arteryto be treated. The balloon portion of the dilation catheter isspecifically advanced across the stenosis or constricted vessel, whereinthe balloon is inflated. Inflation of the balloon dilates thesurrounding vessel and/or displaces the plaque the forms the stenosis.The resulting treated vessel is then characterized by a greatercross-sectional area permitting additional blood flow through thepreviously occluded or constricted region.

Over a period, a previously dilated vessel may narrow. Often thisnarrowing is a result of a vessel “rebounding” from an angioplastyprocedure. In order to prevent vessel rebounding, stents are oftendeployed concurrently with a vessel dilation procedure. A stent ispositioned across the treated dilated region of vasculature where it isradially expanded utilizing a stent delivery catheter. Once properlyseated within the vessel wall, the frame of the stent opposes any inwardradial forces associated with vessel rebounding.

During a PTCA procedure, it is often necessary to finely adjust thepositioning of the stent delivery or balloon dilatation catheter.Improper placement of a stent within a desired region can cause aportion of the treated vessel to narrow, substantially decreasing thebenefits of the initial medical procedure.

Currently, a physician positions the distal end of a balloon dilatationor stent delivery catheter by manually pushing or pulling on theproximal end of the catheter. These pushing and pulling motions must betransmitted through the entire length of the catheter shaft to affectthe catheter's distal tip. The catheter shaft in a medical procedure,however, is usually quite intricately routed within a patient's vascularsystem. The vascular pathlength from the femoral artery to the desiredtreatable artery is usually long and quite tortuous. Manipulations madeby the physician at the catheter's proximal end, therefore, do notnecessarily directly translate to the same movements at the catheter'sdistal end.

Catheters have a natural tendency to compress or elongate irregularlywhen manipulated proximally. More specifically, when advancing acatheter from the catheter's proximal end, the catheter tends to advanceinto and through the curves of vessel walls where they contact a greatersurface area. An advancing catheter, therefore, requires greater forceand displacement at the catheter's proximal end to move the catheter adesired length at the catheter's distal end. In contrast, a retractingcatheter straightens through the curvature of vessel walls causing thecatheter to elongate when withdrawn.

A physician is often required to make a series of advancements andretractions of the catheter to effectively navigate through the tortuousvascular system of a patient. Each advancement and retraction compressesor elongates various sections of the catheter. These compressions andelongations store potential energy throughout the length of the cathetershaft. Coarse manipulations by a physician at the catheter's proximalend may affect the arrangement of these compressions and elongations.Specifically, pulling and pushing of the proximal end of a catheter maycause an unaccounted for release of stored potential energy in thecatheter shaft. This unaccounted for release of energy is called the“backlash” phenomenon. Backlash causes a physician to experience eithera sudden burst or a lag in relative movement of the distal end of thecatheter. This unaccounted for release functionally decreases accuracyin positioning a catheter within a patient's vascular system. Further,even without the issues related to stored energy and backlash, makingthe necessary fine adjustments requires more time and is less accuratethan desirable.

Further complications arise when a physician attempts to inflate thestent delivery or balloon dilation catheter. Before inflation, aphysician must tighten the hemostasis valve around the catheter.Tightening the hemostasis valve, however, may cause the stent deliverycatheter to move out of position. Consequently, the physician is forcedto reposition the catheter once again across the desired vascularregion. As a result, the time spent repositioning the distal end of acatheter causes unnecessary medical expense and further trauma to thepatient.

SUMMARY OF THE INVENTION

The present invention provides a medical device permitting fineadjustments of the distal end of a stent deployment or balloondilatation catheter. In particular, the present invention discloses ahub assembly unit providing a fine adjustment mechanism. The fineadjustment mechanism extends or contracts the length of the hub assemblyunit in controlled incremental units. These controlled finedisplacements are then translated directly to the stent delivery orballoon dilation catheter.

Contrary to coarse adjustments, fine displacements have been found toconserve stored potential energy within a catheter system. A physicianmay therefore incrementally adjust the displacement of the hub assemblyunit of the present invention to accurately and predictably advance orwithdraw a stent delivery or balloon dilation catheter. In the presentinvention, fine adjustments made at the proximal end of the hub assemblyunit directly translate to similar adjustments at the distal end of thecatheter. Thus, the hub assembly unit of the present invention allows aphysician to precisely position a stent delivery or balloon dilationcatheter at a desired point within a desired region of a patient'svasculature.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a side elevation view of a hub assembly unit of the presentinvention, the hub assembly unit being attached to the proximal end of aguide catheter and further receiving a stent delivery catheter at thehub assembly unit's proximal end;

FIG. 2 shows an enlarged cross-sectional elevation view of a turnbucklestyle fine adjustment mechanism embodiment of the hub assembly unit;

FIG. 3 shows a transverse cross-sectional view of a tubular section ofthe hub assembly unit of the present invention, the tubular sectionhaving a lumen of oval shape;

FIG. 4 shows a transverse cross-sectional view of a tubular section ofthe hub assembly unit of the present invention, the tubular sectionhaving a lumen of rectangular shape;

FIG. 5 shows a transverse cross-sectional view of a tubular section ofthe hub assembly unit of the present invention, the tubular sectionhaving a lumen of triangular shape;

FIG. 6 shows a cross-sectional elevation view of an additionalembodiment of the hub assembly unit of the present invention comprisinga lever style fine adjustment mechanism;

FIG. 7 shows a side elevation view of an alternative embodiment of thehub assembly unit of the present invention comprising a rack and pinionstyle fine adjustment mechanism;

FIG. 8 shows a cross-sectional elevation view of a slot and key stylefine adjustment mechanism embodiment of the hub assembly unit of thepresent invention;

FIG. 9 shows a partial key element of the slot and key style fineadjustment mechanism of the present invention comprising a partiallythreaded key;

FIG. 10 shows a slotted track element of the slot and key style fineadjustment mechanism comprising a slotted track in which the partial keyelement travels within;

FIG. 11 shows a threading nut element for the slot and key style fineadjustment mechanism, the threading nut element comprising tworeversibly attaching cylindrical halves that mate when assembled withthe partially threaded key of the partial key element; and

FIG. 12 shows a transverse cross-sectional view of the slot and keystyle fine adjustment mechanism illustrating the seating relationshipsbetween the partial key element, the slotted track element and thethreading nut element.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description should be read with reference to thedrawings, in which like elements in different drawings are numberedidentically. The drawings, which are not necessarily to scale, depictselected embodiments and are not intended to limit the scope of theinvention. Examples of constructions, materials, dimensions andmanufacturing processes are provided for selected elements. Thoseskilled in the art will recognize that many of the examples providedhave suitable alternatives that may be utilized.

Referring now to the drawings, FIG. 1 shows one embodiment of a hubassembly unit 10 of the present invention. Hub assembly unit 10comprises a proximal end 12 and a distal end 14. Distal end 14 includesa linking mechanism 16 connecting hub assembly unit 10 to a firstmedical device 18. In preferred embodiments, first medical device 18 isa catheter, and more specifically, a guide catheter. A proximal fittingis positioned at the proximal end of guide catheter 18 for attaching andfluidly connecting ancillary apparatus to the lumen of guide catheter18. The proximal fitting generally includes at least one male or femalethreaded region on the proximal fitting. Referring specifically to FIG.1, the proximal fitting of guide catheter 18 comprises a female luertype fitting (not shown). As a result, distal end 14 of hub assemblyunit 10 comprises a male luer type fitting (not shown) to properly mateand seat within the guide catheter's proximal fitting. In certainembodiments, the union between hub assembly unit 10 and guide catheter18 is completed using alternative connectors. Additional attachingmechanisms between hub assembly unit 10 and guide catheter 18, beingknown in the art, are also incorporated as within the scope of thepresent invention. In an alternative embodiment, hub assembly unit 10 ispermanently affixed to the body of guide catheter 18.

Proximally from the proximal end of the guide catheter 18 is a firsttubular section 20 of hub assembly unit 10. First tubular section 20comprises a proximal end, a distal end and further comprising a lumenextending the length therethrough. The distal end of first tubularsection 20 includes either a male or a female connector that mates withthe proximal fitting of guide catheter 18. In certain additionalembodiments, first tubular section 20 further comprises a Y-adapter 22.Y-adapter 22 includes a molded section that permits additional medicalapparatus access to the internal lumen of hub assembly unit 10, andfurthermore, access to the lumen of guide catheter 18 when so attached.

First tubular section 20 may additionally comprise a means for securinghub assembly unit 10 during a medical procedure. Proper operation of hubassembly unit 10 requires maintaining hub assembly unit 10 in a singleor fixed position, relative to the patient, during adjustment of the hubassembly during a medical procedure. Medical personnel often hold andmaintain the position of hub assembly unit 10 in this properrelationship during the medical procedure. A suture ring 24, however,may mechanically maintain the positioning of hub assembly unit 10,thereby freeing up medical personnel during the medical procedure. Othermechanical means such as tape and clamps may likewise be used to securehub assembly unit 10 during the medical procedure.

Proximal end 12 of hub assembly unit 10 comprises a second tubularsection 26 having a proximal end, a distal end and a lumen extending thelength therethrough. The proximal end of second tubular section 26preferably includes a hemostasis valve 28, or other fitting capable ofmaintaining the position and orientation of second medical device 30inserted therein. As shown in FIG. 2, second tubular section 26preferably includes a tubular extension or section 27 slidably disposedwithin the lumen of the first tubular section 20. Second medical device30 is advanced to a desired region within a patient's vasculature byinitially inserting second medical device 30 into the proximal end ofsecond tubular section 26. Second medical device 30 is advanced throughthe lumen of second tubular section 26, through the lumen of firsttubular section 20, and finally through the lumen of guide catheter 18,until finally reaching a desired region within the patient'svasculature. In one embodiments of the present invention, second medicaldevice 30 is a stent delivery catheter. In an alternative embodiment ofthe present invention, second medical device 30 is a balloon dilationcatheter.

Hemostasis valve 28, or the like, mechanically constricts about theouter diameter of second medical device 30, hermetically sealing theatmospherically exposed portion of second medical device 30 from theinternally advanced portions of second medical device 30. Thishemostatic measure concurrently affixes second medical device 30 into asingle longitudinal and rotational orientation. The mechanical pressureapplied by hemostatsis valve 28 maintains this single orientation whilehemostasis valve 28 is actively engaged with second medical device 30.

Fine adjustment mechanism 32 connects and maintains the position of theproximal end of first tubular section 20 with or relative to the distalend of second tubular section 26. Fine adjustment mechanism 32additionally engages either first tubular section 20, second tubularsection 26, or both tubular sections. Fine adjustment mechanism 32additionally provides a mechanical means for displacing the two tubularsections with respect to one another. In particular, fine adjustmentmechanism 32 extends or contracts the length of hub assembly unit 10 bydisplacing the spatial relationship between first tubular section 20 andsecond tubular section 26. As shown, internal threads on the fineadjustment mechanism mate with threads on the two tubular sections andfunctions as a turnbuckle when rotated to draw the member together orapart.

In preferred embodiments, fine adjustment mechanism 32 may expand orcontract the length of hub assembly unit 10 by a total of 1 to 3centimeters. Most preferably, hub assembly unit 10 may be displaced atotal of 1 to 2 centimeters. Units of measurement 33 are placed upon hubassembly unit 10 to aid physicians in gauging spatial displacement ofhub assembly unit 10 during a medical procedure.

In a preferred embodiment, a guide catheter is first advanced to adesired region within a patient's vasculature. Hub assembly unit 10 isthen attached to the proximal end of the advanced guide catheter, if notalready attached. A second medical device 30 is then advanced to adesired region within the patient's vasculature by initially insertingthe second medical device 30 into the proximal end of second tubularsection 26 of hub assembly unit 10. The second medical device 30 is thenadvanced through the lumen of second tubular section 26, through thelumen of first tubular section 20, and finally through the lumen ofguide catheter 18. Second medical device 30 is then coarsely positionedat approximately the desired region within a patient's vasculature.

A physician may make coarse adjustments to second medical device 30 bymanually pushing and pulling on the proximal end of second medicaldevice 30. Coarse manual adjustments allow a physician to position thedistal end of second medical device 30 approximately at a desired pointwithin a desired region within the patient's vasculature. As describedearlier, however, the length of second medical device makes preciseplacement difficult. Manipulations made by the physician at the proximalend of second medical device 30 do not necessarily translate to the samemotions at the distal end of second medical device 30. Compression orelongation of second medical device 30, caused by second medical device30 following the tortuous vasculature of the patient, results in secondmedical device 30 retaining an unaccountable amount of stored potentialenergy. Small coarse adjustments, therefore, may release this storedenergy causing a physician to overshoot a desired target. The presentinvention overcomes the problem associated with the release of storedpotential energy within an advanced catheter.

After second medical device 30 is coarsely positioned within thepatient's vasculature, hemostasis valve 28 is mechanically engaged.Hemostatsis valve 28 hemostatically preferably affixes second medicaldevice 30 into a single longitudinal and rotational orientation. As aresult, movements made by hub assembly unit 10 and/or guide catheter 18are directly translated to the second medical device 30. Fine adjustmentmechanism 32 provides for minor spatial advancements or retreats of thecatheter system. In particular, fine adjustment mechanism 32 extends orcontracts the length of hub assembly unit 10 by displacing the spatialrelationship between first tubular section 20 and second tubular section26. These fine displacements are then translated to second medicaldevice 30.

Contrary to coarse adjustments, fine displacements have been found toconserve stored potential energy within a catheter system. The presentinvention allows a physician to incrementally adjust the positioning ofsecond medical device 30 within a patient's vasculature. Specifically, aphysician may accurately advance or withdraw second medical device 30 byfractions of a millimeter through proper operation of fine adjustmentmechanism 32. A physician may incrementally adjust the spatialrelationships within hub assembly unit 10 to accurately and predictablyadvance or withdraw a second medical device up to a total distance ofapproximately 3 centimeters. Fine adjustments made at the proximal endof a catheter system, therefore, directly translate to similaradjustments at the distal end of the catheter system in the presentinvention. Thus, hub assembly unit 10 allows a physician to preciselyposition a second medical device 30 at a desired point within thedesired region of a patient's vasculature.

Refer now to FIG. 2, wherein an enlarged cross-sectional elevation viewof the turnbuckle style fine adjustment mechanism 40 embodiment isshown. With respect to FIG. 2, a distal portion of second tubularsection 26 includes a tubular extension or section 27 that is slidablydisposed within the lumen of first tubular section 20. At thedistal-most end 36 of second tubular section 26 is an O-ring 34. O-ring34 engages both second tubular section 26 and the lumen wall of firsttubular section 20. When second tubular section 26 is slidably displacedalong the length of the lumen of first tubular section 20, O-ring 34hemostatically prevents or reduces blood or other bodily fluids frombeing displaced between the outer wall of second tubular section 26 andthe inner wall of first tubular section 20. This relationship betweenfirst tubular section 20 and second tubular section 26 may likewise bereversed wherein first tubular section 20 may be slidably disposedwithin the lumen of second tubular section 26. In yet anotherembodiment, both the proximal-most end of first tubular section 20 andthe distal-most end of second tubular section 26 terminate within fineadjustment mechanism 32. In this embodiment, fine adjustment mechanism32 maintains fluid communication between the two tubular sections, aswell as provides a location for the two sections to be slidablydisposed.

In the illustrated turnbuckle style fine adjustment mechanism 40, aportion of proximal end 42 of first tubular section 20 and a portion ofdistal portion 44 of second tubular section 26 are threaded. Thedirection of threading on tubular section 20 is the reverse of thedirection of threading on tubular section 26. One tubular section isright hand threaded and the other tubular section is left hand threaded.Thus, in this particular embodiment, the threading of each tubularsection is never the same.

Threading nut 46 overlays the threaded portions 42, 44 of first andsecond tubular sections 20 and 26. Complementary threads 48, to bothleft and right handed threaded portions 44 and 42, are manufactured intothreading nut 46. In a preferred embodiment, complementary threads 48are molded into threading nut 46. Complimentary threads 48 extendinwardly from the ends of threading nut 46 to a location approximatingthe center 50 of threading nut 46. At the center 50, complimentarythreads 48 terminate, defining the ends of two threaded tracks.

The threaded tracks provide a pathlength for which threaded tubularsections 42 and 44 may travel. Threaded tubular section 42 and 44 travelalong the threaded tracks through the appropriate rotation of threadednut 46. Rotation of threading nut 46 in a clockwise direction causesboth first tubular section 20 and second tubular section 26 to both moveeither inwardly or outwardly, depending upon the direction of thethreads. Inward or outward directional movement occurs in unison becausethreading nut 46 controls the rate of both threaded tubular sections 42and 44 at the same time. Likewise, rotation of threading nut 46 in thecounter-clockwise direction causes the tubular sections to move inunison in the opposite direction as the first.

When threading nut 46 is rotated, complementary threads 48 guide boththreaded tubular sections 42 and 44 along their respective threadedtracks. Since threaded tubular sections 42 and 44 are merely portions offirst tubular section 20 and second tubular section 26, respectively,movement of threaded tubular sections 42 and 44 are translated as anextension or contraction of hub assembly unit 10 as a whole. The lengthof hub assembly unit 10, therefore, may be extended or contracted by theproper rotation of threading nut 46, thereby allowing a physician toprecisely position a second medical device 30 at a desired point withina desired region of a patient's vasculature.

Extension of the hub assembly unit 10 is proportional to the length ofthe threading nut 46. As such, hub assembly unit 10 may be lengthened adistance until the threaded portions 44 and 42 disengage from thethreading nut 46. Similarly, the length of hub assembly unit 10 may becontracted until the complementary threading 48 ceases within the center50 of threading nut 46. In preferred embodiments, turnbuckle style fineadjustment mechanism 40 may expand or contract the length of hubassembly unit 10 by a total of 0.5 to 3 centimeters. Most preferably,hub assembly unit 10 may be displaced a total of 1 to 2 centimeters.Each rotation of threaded nut 46 correlates to an incrementaldisplacement of hub assembly unit 10. In preferred embodiments, eachrotation of threaded nut 46 spatially displaces hub assembly unit 10 by1 to 6 millimeters.

Turnbuckle style fine adjustment mechanism 40 may be modified in orderto adjust the rate and distance threaded tubular sections 42 and 44travel within threaded nut 46. One modification includes manufacturingthreads of threaded tubular section 42, and its complementary threads 48in threaded nut 46, more fine (having more threads per linearcentimeter) than the other threaded tubular section 44. As a result ofthis modification, the rotation of threaded nut 46 causes one threadedtubular section 44 to extend or contract farther and faster than itsfinely threaded counterpart 42. Likewise, only threaded tubular section44 and its complementary threads 48 may be manufactured with finethreading.

Operation of turnbuckle style fine adjustment mechanism 40 causesexerted rotational energy performed by threading nut 46 to transfer tosurrounding apparatus. In this case, transferred rotational energy tendsto affect either first tubular section 20 or second tubular section 26.The present invention channels this rotational energy from threading nut46 into a longitudinal force that causes the spatial displacement of thetwo tubular section 20 and 26 within hub assembly unit 10.

Rotational energy has a propensity to remain as rotational energy. Thus,by leaving the above-described system alone, exerted rotational energyfrom threading nut 46 would cause first tubular section 20 and secondtubular section 26 to additionally rotate. In order to transform thisrotational energy into other forms of work, the rotational energy mustbe redirected. The present invention transforms exerted rotationalenergy into a longitudinal motive force.

Securing suture ring 24, or the like, generally restrains first tubularsection 20 to a single orientation. Transferred rotational energy fromthreading nut 46 is therefore refrained from affecting the rotationalorientation of first tubular section 20. Second tubular section 26,however, generally remains free to be affected by such transferredrotational energy. Modifications to the shape of tubular sections 20 and26 can redirect this transferred rotational energy into a functional,longitudinal motive force.

Refer now to FIG. 3, wherein a transverse cross-sectional view at 3-3 ofhub assembly unit 10 is shown. The cross-section taken at 3-3 includesportions of both first tubular section 20 and second tubular section 26.Specifically, the cross-section shows a distal extension 27 of secondtubular section 26 seated within first tubular section 20. The innerlumen of first tubular section 20 is non-circular in shape. Morespecifically, the inner lumen of first tubular section 20 is oval. Theouter diameter of second tubular section 26 is complementary oval shapedto properly seat within the inner lumen of first tubular section 20.This non-circular lumen design provides torsional resistance.Specifically, the oval shaped lumen configuration prevents secondtubular section 26 from spinning within first tubular section 20 whenthreading nut 46 is rotated. In effect, the oval-shaped design channelstransferred rotational energy from threading nut 46 into a longitudinalmotive force. This longitudinal motive force displaces second tubularsection 26 and first tubular section 20 in a single longitudinal androtational plane. Transferred energy is then transformed into work thatdisplaces the two tubular sections 20 and 26 along the manufactured ovalshaped lumen pathlength.

FIG. 4 is an additional embodiment showing a transverse cross-sectionalview at 3-3 of hub assembly unit 10. The cross-section of thisparticular embodiment similarly includes portions of both first tubularsection 20 and second tubular section 26. Specifically, thecross-section includes the distal extension 27 of second tubular section26 seated within the lumen of first tubular section 20. In FIG. 4,however, the inner lumen of first tubular section 20 is non-circularrectangular shaped. The outer diameter of second tubular section 26 iscomplementary rectangular shaped to properly seat within the inner lumenof first tubular section 20. This rectangular shaped lumen designadditionally provides torsional resistance within hub assembly unit 10.Specifically, the four elongated regions of the rectangular shaped lumenconfiguration prevent second tubular section 26 from spinning withinfirst tubular section 20 when threading nut 46 is rotated. Therectangular shaped design further channels transferred rotational energyfrom threading nut 46 into a longitudinal motive force. Thislongitudinal motive force displaces second tubular section 26 and firsttubular section 20 in a single longitudinal and rotational plane.Transferred energy is then transformed into work that displaces the twotubular sections 20 and 26 along the manufactured rectangular shapedlumen pathlength.

FIG. 5 is yet another embodiment showing a transverse cross-sectionalview at 3-3 of hub assembly unit 10. The cross-section of thisparticular embodiment again includes portions of both first tubularsection 20 and second tubular section 26. Specifically, thecross-section includes the distal extension 27 of second tubular section26 seated within first tubular section 20. In FIG. 5, however, the innerlumen of first tubular section 20 is triangular shape. To properly seatwithin the inner lumen of first tubular section 20, the outer diameterof second tubular section 26 is complementary triangular shaped. Thistriangular shaped lumen design additionally provides torsionalresistance within hub assembly unit 10. Specifically, the threeelongated regions of the triangular shaped lumen configuration preventsecond tubular section 26 from spinning within first tubular section 20when threading nut 46 is rotated. The triangular shaped design furtherchannels transferred rotational energy from threading nut 46 into alongitudinal motive force. This longitudinal motive force displacessecond tubular section 26 and first tubular section 20 in a singlelongitudinal and rotational plane. Transferred energy is thentransformed into work that displaces the two tubular sections 20 and 26along the manufactured triangular shaped lumen pathlength.

The inner lumen of second tubular section 26 need not necessarily beoval shaped, rectangular shaped or triangular shaped (as depicted inFIGS. 3, 4 and 5, respectively). Torsional resistance is an outgrowth ofthe friction fit between the inner lumen diameter of first tubularsection 20 and the outer diameter of second tubular section 26. As aresult, the inner lumen configuration of second tubular section 26 maybe circular without affecting the torsional resistance characteristicsof the present invention provided there is sufficient friction betweenthe members.

Refer now to FIG. 6, wherein a cross-sectional elevation view of anadditional embodiment of hub assembly unit 10 is shown comprising alever style fine adjustment mechanism 50. Lever style fine adjustmentmechanism 50 similarly comprises a portion of the proximal-most end offirst tubular section 20 and a distal portion of second tubular section26. The distal portion of second tubular section 26 includes twodistinct regions, a first distal portion 35 and a second distal portion37, both having lumens running the length therein. First distal portion35 attaches at a proximal end to a hemostasis valve (not shown) or otherfitting capable of maintaining the position and orientation of a secondmedical device inserted the length therethrough. Second distal portion37, on the other hand, is slidably disposed within the lumen of firsttubular section 20. Because second distal portion 37 is slidablydisposed within first tubular section 20, the lever style fineadjustment mechanism 50 maintains a fluid connection between theproximal end 12 to the distal end 14 of hub assembly unit 10.

At the distal-most end of second distal portion 37 is a seal, such as anO-ring 34. O-ring 34 engages both the distal-most end of second distalportion 37 and the lumen wall of first tubular section 20. When thedistal-most end of second distal portion 37 is slidably displaced alongthe length of the lumen of first tubular section 20, O-ring 34hemostatically prevents blood or other bodily fluids from beingdisplaced between the outer wall of the distal-most end of second distalportion 37 and the inner wall of first tubular section 20.

With particularity to FIG. 6, lever style fine adjustment mechanism 50is a three-lever arm mechanism. Affixed to first distal portion 35 andfirst tubular section 20 are two anchoring devices 52 and 53. Anchoringdevice 52 is affixed to first distal portion 35, whereas anchoringdevice 53 is affixed to first tubular section 20. Anchoring devices 52and 53 are preferably molded to hub assembly unit 10. However, othersuitable attachment procedures known in the art may also be utilized.Anchoring devices 52 and 53 additionally provide an attachment point forfirst lever arm 54 and second lever arm 56, respectively. First leverarm 54 and second lever arm 56 are both comprised of a generally rigidmaterial and have a proximal end and a distal end. The proximal ends ofboth lever arms 54 and 56 are pivotally attached to their correspondinganchoring device. The distal end of first lever arm 54 is hinged 58 to aportion of second lever arm 56. Second lever arm 56, therefore, ispreferably longer than first lever arm 54. The third lever arm withinlever style fine adjustment mechanism 50 includes the portion of hubassembly unit 10 wherein second distal portion 37 is slidably disposedwithin the lumen of first tubular section 20. Because the third leverarm is comprised of two slidably disposed portions, the third lever armis variable in length.

A physician operates lever style fine adjustment mechanism 50 by raisingand lowering distal end 57 of second lever arm 56. Raising distal end 57of second lever arm 56 slidably displaces second distal portion 37within first tubular section 20. As a result, the length of hub assemblyunit 10 decreases. Lowering distal end 57 of second lever arm 56, on theother hand, slidably displaces second distal portion 37 apart from firsttubular section 20. With this lever arm movement, the length of hubassembly unit 10 increases. Lever style fine adjustment mechanism 50,therefore, provides a physician with a medical device for finelyadjusting the positioning of a second medical device 30. Morespecifically, lever style fine adjustment mechanism 50 allows aphysician to precisely position a stent delivery catheter without theconcern of a potential energy release associated with coarseadjustments.

Movement within the lever style fine adjustment mechanism 50 occurs in asingle plane. All lever arms are hinged or fixed to operate within thissingle plane. As a result, little to no rotation occurs while extendingand contracting the variable length third arm of hub assembly unit 10.Second distal portion 37 may be slidably disposed within the lumen ofthe first tubular section 20 in a oval shaped, a rectangular shaped or atriangular shaped lumen design to further prevent rotation within leverstyle fine adjustment mechanism 50, as described in detail withreference to FIGS. 3, 4 and 5.

Refer now to FIG. 7, wherein a side elevation view of an alternativeembodiment of hub assembly unit 10 is shown comprising a rack and pinionstyle fine adjustment mechanism 60. Rack and pinion style fineadjustment mechanism 60 similarly comprises a portion of theproximal-most end of first tubular section 20 and a distal portion ofsecond tubular section 26. The distal portion of second tubular section26 additionally includes two distinct regions, a first distal portion 35and a second distal portion 37, both having lumens running the lengththerein. First distal portion 35 attaches at a proximal end tohemostasis valve 28, or other fitting capable of maintaining theposition and orientation of a second medical device 30 inserted thelength therethrough. Second distal portion 37, on the other hand, ishemostatically, slidably disposed within the lumen of first tubularsection 20. The two sections maintain a fluid connection betweenproximal end 12 to distal end 14 of hub assembly unit 10 because seconddistal portion 37 is hemostatically, slidably disposed within firsttubular section 20.

With particularity to rack and pinion style fine adjustment mechanism60, a rack 64 spans between first tubular section 20 and second tubularsection 26. Rack 64 is characterized by a row of teeth 65 that extentoutwardly away from the body of hub assembly unit 10. A first end ofrack 64 is affixed to first tubular section 20 by first anchoringelement 63. The second end of rack 64 is slidably affixed to firstdistal portion 35 by second anchoring element 62 and pinion 66. Secondanchoring element 62 is affixed to first distal portion 35. Attached tosecond anchoring element 62 is pinion 66. Pinion 66 comprises a cogwheelhaving a series of teeth 67 on the rim of pinion 66. Through engagementwith complementary teeth 65 of rack 64, pinion 66 transmits a horizontalmotive force to rack 64. To aid in slidably disposing rack 64 throughpinion 66 rotation, a recessed track incorporating a friction-reducingsurface may be added to first distal portion 35.

A physician operates rack and pinion style fine adjustment mechanism 60by rotating pinion 66 on rack 64. With respect to FIG. 7, rotation ofpinion 66 in a clockwise fashion slidably displaces second distalportion 37 within first tubular section 20. As a result, the length ofhub assembly unit 10 decreases. Rotation of pinion 66 in acounter-clockwise fashion, on the other hand, slidably displaces seconddistal portion 37 apart from first tubular section 20, therebylengthening hub assembly unit 10. Rack and pinion style fine adjustmentmechanism 60, therefore, provides a physician with a medical device forfinely adjusting a second medical device 30 within a patient'svasculature. More specifically, rack and pinion style fine adjustmentmechanism 60 allows a physician to precisely position a second medicaldevice 30 without backlash, which is commonly associated with coarsemanual adjustments.

Refer now to FIG. 8, wherein a cross-sectional elevation view of anotherembodiment of hub assembly unit 10 is shown having a slot and key stylefine adjustment mechanism 70. Slot and key style fine adjustmentmechanism 70 is comprised of a partial key element 71 (see FIG. 9), aslotted track element 80 (see FIG. 10) and a threading nut element 90(see FIG. 11).

FIG. 9 illustrates, in detail, partial key element 71. Partial keyelement 71 comprises a first tubular section 72 having a proximal end, adistal end and a lumen 102 running the length therethrough. Affixedalong a portion of first tubular section 72 is a partially threaded key74. Partially threaded key 74 is preferably molded onto, or is a part offirst tubular section 72. Partially threaded key 74 comprises raisedthreaded sections 76 and further comprises two first planar surfaces 78.First planar surfaces 78 are manufactured on partially threaded key 74in a parallel relationship. The distance between first planar surfaces78 further define a width for partially threaded key 74.

At the distal end of first tubular section 72 is a seal, such as anO-ring 34. O-ring 34 engages both the distal end of first tubularsection 72 and the lumen wall of second tubular section 82 of slottedtrack element 80. When the distal end of first tubular section 72 isslidably displaced along the length of the lumen of second tubularsection 82, O-ring 34 hemostatically prevents blood or other bodilyfluids from being displaced between the outer wall of first tubularsection 72 and the inner wall of second tubular section 82.

FIG. 10 illustrates a detailed perspective view of slotted track element80. Slotted track element 80 comprises a second tubular section 82having a proximal end 83, a distal end and a lumen extending the lengththerethrough. Proximal end 83 terminates into a first washer-like disc84 that extends radially from second tubular section 82. At a locationdistal from proximal end 83 is a second washer-like disc 85 thatadditionally extends radially from second tubular section 82. Betweenfirst washer-like disc 84 and second washer-like disc 85 is slottedtrack 86.

Slotted track 86 comprises a portion of second tubular section 82preferably having a first and a second opening. It is, however,recognized that a single opening could also be utilized. First andsecond openings possess identical widths and lengths and areadditionally positioned on opposing sides of second tubular section 82.The widths of first and second openings are substantially the same asthe distance between first planar surfaces 78 defining the width ofpartially threaded key 74. As such, partially threaded key 74 may beslidably disposed with slotted track 86 when positioned therein.

In order to position partially threaded key 74 within slotted track 86,slotted track element 80 includes a line of separation 88. Line ofseparation 88 extends along a portion of the length of slotted trackelement 80, dividing slotted track 86 into two sections. Once the twosections of slotted track element 80 are separated, first tubularsection 72 is disposed within second tubular section 82. Partiallythreaded key 74 is then advanced to and aligned within the separatedsections of slotted track 86. Once properly aligned within the separatedsection of slotted track 86, the two separated sections are againre-adhered.

Threading nut element 90 is positioned between first and secondwasher-like discs 84 and 85. Additionally, threading nut element isdisplaced over partially threaded key 74. In this configuration,threading nut element 90 provides a horizontal motive force upon partialkey element 71 when rotated. FIG. 11 illustrates a detailed perspectiveview of threading nut element 90. In a preferred embodiment, the lengthof threading nut element 90 is equivalent to the length between firstand second washer-like discs 84 and 85.

Threading nut element 90 includes two half sections 92 and 94. The innerlumen wall of half sections 92 and 94 include a machine threading 96.Machine threading 96 complementarily matches threading 76 on partiallythreaded key 74. Threading nut element 90 further comprises at least onepress-fit pin 98 and its complementarily recessed hole 100. Press-fitpin 98 is positioned on half section 92 to properly align threading 96between the two half sections 92 and 94. Proper alignment is importantto provide a smooth continuous threading when the two half sections 92and 94 are adhered. Press-fit pin 98 interference fits within recessedhole 100 in half section 94 to additionally prevent separation of halfsection 92 and 94 during operation.

Referring back to FIG. 8, luer connection 17 connects hub assembly unit10 to a first medical device (not shown). In preferred embodiments, thefirst medical device is a catheter, and more specifically, a guidecatheter. Additional attaching mechanisms between hub assembly unit 10and the guide catheter, being known in the art, are also incorporated aswithin the scope of the present invention. In an alternative embodiment,hub assembly unit 10 is permanently affixed to the structure of theguide catheter.

Proximally from luer connector 17 is second tubular section 82 of hubassembly unit 10. Second tubular section 82 comprises a proximal end, adistal end and a lumen extending the length therethrough. As illustratedin FIG. 8, second tubular section 82 further includes channel 104 forpartial key element 71 to be slidably displaced therein.

Although not shown, second tubular section 82 may comprise a means forsecuring hub assembly unit 10 during a medical procedure. Properoperation of hub assembly unit 10 requires maintaining hub assembly unit10 in a single position, relative to the patient, during a medicalprocedure. A suture ring (not shown), may mechanically maintain the hubassembly unit's positioning during the medical procedure. Othermechanical means such as tape and clamps may likewise be used to securehub assembly unit 10 during the medical procedure.

Extending from the proximal end 83 of second tubular section 82 is aportion of partial key element 71, specifically first tubular section72. The proximal end of first tubular section 72 includes a hemostasisvalve (not shown) or other fitting capable of maintaining the positionand orientation of a second medical device inserted therein. The secondmedical device is advanced to a desired region within a patient'svasculature by initially inserting the second medical device into theproximal end of first tubular section 72. The second medical device isthen advanced through the lumen of first tubular section 72, through thelumen of second tubular section 82, and finally through the lumen of theguide catheter until finally reaching a desired region within thepatient's vasculature. In one embodiment of the present invention, thesecond medical device is a stent delivery catheter. In an alternativeembodiment of the present invention, the second medical device is aballoon dilation catheter.

The distal end of partial key element 71 additionally extends into slotand key style fine adjustment mechanism 70. FIG. 8 illustrates thepositioning of partially threaded key 74 within slotted track 86 of slotand key style fine adjustment mechanism 70. FIG. 8 further illustratesthe positioning of threading nut element 90 between first and secondwasher-like discs 84 and 85, and further over partially threaded key 74.

A physician operates slot and key style fine adjustment mechanism 70 byrotating threading nut element 90, when assembled as shown in FIG. 8.When threading nut element 90 is rotated, complementary threads 96 guidepartially threaded key 74 either up or down slotted track 86. Sincepartially threaded key 74 is merely a portion of first tubular section72, movement of partially threaded key 74 translates as an extension ora contraction of hub assembly unit 10 as a whole. The length of hubassembly unit 10, therefore, may be extended or contracted by the properrotation of threading nut element 90, thereby allowing a physician toprecisely position a second medical device 30 at a desired point withina desired region of a patient's vasculature.

Extension and contraction of hub assembly unit 10 is proportional to thepathlength with which partially threaded key 74 may travel withinslotted track 86. In preferred embodiments, slot and key style fineadjustment mechanism 70 may expand or contract the length of hubassembly unit 10 by a total of 0.5 to 3 centimeters. Most preferably,hub assembly unit 10 may be displaced a total of 1 to 2 centimeters.Each rotation of threaded nut element 90 correlates to an incrementaldisplacement of hub assembly unit 10. The length of incrementaldisplacement associated with each rotation is a product of the size ofthe threading on partially threaded key 74 and complementary threads 96on threaded nut element 90. Finer threading provides for smallincremental displacements for each rotation. In preferred embodiments,each rotation of threaded nut element 90 spatially displaces hubassembly unit by 1 to 6 millimeters.

Refer now to FIG. 12, wherein a transverse cross-sectional view of slotand key style fine adjustment mechanism 70 is shown. FIG. 12 furtherillustrates the spatial relationships between partial key element 71,slotted track element 80 and threading nut element 90. In particular,FIG. 12 illustrates partially threaded nut 74 within slotted trackelement 80.

Numerous characteristics and advantages of the invention covered by thisdocument have been set forth in the foregoing description. It will beunderstood, however, that this disclosure is, in many respects, onlyillustrative. Changes may be made in details, particularly in matters ofshape, size and ordering of steps without exceeding the scope of theinvention. The invention's scope is of course defined in the language inwhich the appended claims are expressed.

1. A method for placing and positioning a delivery catheter at a desiredlocation in a vascular system, the method comprising the steps of:advancing a guide catheter having a proximal end, a distal end and alumen extending the length therethrough within the vascular system;providing a hub assembly, the hub assembly being hemostatically affixedto and in fluid communication with the proximal end of the guidecatheter, the hub assembly further including a fine adjustment mechanismcapable of extending or contracting the hub assembly unit from a firstlength to a second length; advancing a delivery catheter having aproximal end, a distal end and a lumen extending the length therethroughwithin the hub assembly and through the guide catheter until reaching adesired region; and positioning the distal end of the delivery catheterprecisely across a desired point within the desired region using thefine adjustment mechanism.
 2. The method of claim 1, wherein rotation ofthe delivery catheter is prohibited while positioning the distal end ofthe delivery catheter using the fine adjustment mechanism.
 3. The methodof claim 1, wherein longitudinal movement of the guide catheter isprohibited while positioning the distal end of the delivery catheterusing the fine adjustment mechanism.
 4. The method of claim 1, whereinthe guide catheter includes a means for securing the guide catheter in afixed position relative to a patient.
 5. The method of claim 1, whereinthe fine adjustment mechanism comprises a turnbuckle mechanism.
 6. Themethod of claim 1, wherein the fine adjustment mechanism comprises arack and pinion mechanism.
 7. A method for placing and positioning amedical device at a desired location in a vascular system, the methodcomprising the steps of: advancing a first medical device having aproximal portion, a proximal end, a distal end and a lumen extending thelength therethrough within the vascular system until the distal end ofthe first medical device reaches a first desired region; advancing asecond medical device having a proximal portion, a proximal end and adistal end within the lumen of the first medical device until the distalend of the second medical device reaches a second desired region distalof the first desired region; providing a fine adjustment mechanism, thefine adjustment mechanism attached to the proximal portion of the firstmedical device and the proximal portion of the second medical device;actuating the fine adjustment mechanism wherein the distal end of thesecond medical device is translated proximally or distally relative tothe distal end of the first medical device.
 8. The method in claim 7,wherein the second medical device is translated proximally or distallyrelative to the distal end of the first medical device by rotating thefine adjustment mechanism.
 9. The method in claim 7, wherein the fineadjustment mechanism includes a lumen extending therethrough, whereinthe second medical device extends through the lumen.
 10. The method inclaim 7, wherein the fine adjustment mechanism comprises a turnbucklemechanism.
 11. The method in claim 7, wherein the fine adjustmentmechanism comprises a rack and pinion mechanism.
 12. A method forplacing and positioning a delivery catheter at a desired location in avascular system, the method comprising the steps of: advancing a guidecatheter having a proximal end, a distal end and a lumen extending thelength thererthrough within the vascular system; providing a hubassembly, the hub assembly having a proximal end, a distal end and alumen extending therethrough and in fluid communication with the lumenof the guide catheter, wherein the distal end of the hub assembly isconnected to the proximal end of the guide catheter; advancing adelivery catheter having a proximal end and a distal end within the hubassembly lumen and the guide catheter lumen until the distal end of thedelivery catheter reaches a desired region distal of the guide catheter;providing a fine adjustment mechanism, the fine adjustment mechanismconnected to the proximal end of the hub assembly and the proximal endof the delivery catheter; actuating the fine adjustment mechanismwhereby the delivery catheter is longitudinally extended or contractedrelative to the guide catheter.
 13. The method of claim 12, wherein theproximal end of the delivery catheter includes a hemostatsis valve. 14.The method of claim 12, wherein the fine adjustment mechanism isactuated by rotating the fine adjustment mechanism.
 15. The method ofclaim 12, wherein the fine adjustment mechanism comprises a turnbucklemechanism.
 16. The method of claim 12, wherein the fine adjustmentmechanism includes a lumen extending therethrough, wherein the deliverycatheter extends through the lumen.